std::counting_semaphore<LeastMaxValue>:: acquire

#include <array>
#include <chrono>
#include <cstddef>
#include <iomanip>
#include <iostream>
#include <mutex>
#include <new>
#include <random>
#include <semaphore>
#include <thread>
#include <vector>
using namespace std::literals;
constexpr std::size_t max_threads{10U}; // modifiez et observez l'effet
constexpr std::ptrdiff_t max_sema_threads{3}; // {1} pour sémaphore binaire
std::counting_semaphore semaphore{max_sema_threads};
constexpr auto time_tick{10ms};
unsigned rnd()
{
    static std::uniform_int_distribution<unsigned> distribution{2U, 9U}; // [delais]
    static std::random_device engine;
    static std::mt19937 noise{engine()};
    return distribution(noise);
}
class alignas(std::hardware_destructive_interference_size) Guide
{
    inline static std::mutex cout_mutex;
    inline static std::chrono::time_point<std::chrono::high_resolution_clock> started_at;
    unsigned delay{rnd()}, occupy{rnd()}, wait_on_sema{};
public:
    static void start_time() { started_at = std::chrono::high_resolution_clock::now(); }
    void initial_delay() { std::this_thread::sleep_for(delay * time_tick); }
    void occupy_sema()
    {
        wait_on_sema =
            static_cast<unsigned>(std::chrono::duration_cast<std::chrono::milliseconds>(
                std::chrono::high_resolution_clock::now() - started_at -
                delay * time_tick).count() / time_tick.count());
        std::this_thread::sleep_for(occupy * time_tick);
    }
    void visualize(unsigned id, unsigned x_scale = 2) const
    {
        auto cout_n = [=](auto str, unsigned n)
        {
            for (n *= x_scale; n-- > 0; std::cout << str)
                ;
        };
        std::lock_guard lk{cout_mutex};
        std::cout << '#' << std::setw(2) << id << ' ';
        cout_n("░", delay);
        cout_n("▒", wait_on_sema);
        cout_n("█", occupy);
        std::cout << '\n';
    }
    static void show_info()
    {
        std::cout << "\nThreads: " << max_threads << ", Débit: " << max_sema_threads
                  << " │ Légende : délai initial ░░ │ état d'attente ▒▒ │ occupation du sémaphore ██ \n"
                  << std::endl;
    }
};
std::array<Guide, max_threads> guides;
void workerThread(unsigned id)
{
    guides[id].initial_delay(); // simuler un travail avant l'acquisition du sémaphore
    semaphore.acquire();        // attendre qu'un emplacement de sémaphore libre soit disponible
    guides[id].occupy_sema();   // simuler un travail pendant que le sémaphore est acquis
    semaphore.release();
    guides[id].visualiser(id);
}
int main()
{
    std::vector<std::jthread> threads;
    threads.reserve(max_threads);
    Guide::show_info();
    Guide::start_time();
    for (auto id{0U}; id != max_threads; ++id)
        threads.push_back(std::jthread(workerThread, id));
}